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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 21 |
| 4 | 91140 |
| 5 | 2974547521 |
| 6 | 410969810835855 |
| 7 | 204186348024605926840 |
| 8 | 319377442011213173229914216 |
| 9 | 1409441402075134083081734769337800 |
| 10 | 16021054958659349444630042183181806132953 |
[0,0,21,91140,2974547521,410969810835855, 204186348024605926840,319377442011213173229914216, 1409441402075134083081734769337800, 16021054958659349444630042183181806132953] |